/*
 * Code taken from 
 * http://www.experts-exchange.com/Programming/Programming_Languages/
 *      Java/Q_20273040.html
 * Posted by PingBanon on 03/11/2005 06:41AM PST
 */

public class ByteArrayUtils {
    public static final int   NUMBER_OF_BITS_IN_A_BYTE = 8;
    public static final short MASK_TO_BYTE             = 0xFF;
    public static final int   SIZE_OF_AN_INT_IN_BYTES  = 4;

    public static void writeInt( byte[] p_dest,  
				 int    p_toWrite )
    {
	assert( p_dest.length >= SIZE_OF_AN_INT_IN_BYTES )
	    : "Programming error: p_dest is too short to hold an int";
	
	// unrolled loop of 4 iterations
	p_dest[0] = (byte)(p_toWrite & MASK_TO_BYTE);
	p_toWrite >>= NUMBER_OF_BITS_IN_A_BYTE;
    
	p_dest[1] = (byte)(p_toWrite & MASK_TO_BYTE);
	p_toWrite >>= NUMBER_OF_BITS_IN_A_BYTE;

	p_dest[2] = (byte)(p_toWrite & MASK_TO_BYTE);
	p_toWrite >>= NUMBER_OF_BITS_IN_A_BYTE;

	p_dest[3] = (byte)(p_toWrite & MASK_TO_BYTE);
    }

    public static int readInt( byte[] p_src ) // must be of size 4
    {
	assert( p_src.length >= SIZE_OF_AN_INT_IN_BYTES )
	    : "Programming error: p_src is too short to hold an int";

	// unrolled loop of 4 iterations
	int result = (   p_src[ 0 ] & MASK_TO_BYTE );
	result    |= ( ( p_src[ 1 ] & MASK_TO_BYTE ) << 8 );
	result    |= ( ( p_src[ 2 ] & MASK_TO_BYTE ) << 16 );
	result    |= ( ( p_src[ 3 ] & MASK_TO_BYTE ) << 24 );

	return result;
    }
}